Microwave Thermokeratoplasty (MTK) shrinks the stromal (middle) layer of the cornea in a ring pattern around the pupil in response to elevation of temperature by absorption of microwave energy; the central cornea flattens as a result, thus correcting for myopia. About 50% of the U.S. population requires correction for myopia. This novel method has advantages over the most common surgical treatment for myopia, laser assisted in-situ keratomileusis (LASIK). Specifically, MTK: [unreadable] Involves no surgical intervention in the central cornea. [unreadable] Requires no period of healing. [unreadable] Does not use expensive equipment. [unreadable] Involves only a single, 2-second treatment. [unreadable] Spares the corneal epithelium through its cooling system. [unreadable] Avoids the dry eye complication characteristic of LASIK. We will improve the existing MTK system by incorporating a feedback system to achieve precise results and an optical centering system to assist placement on the cornea. We will evaluate the redesigned system in ex vivo and in vivo corneas and quantify the improvement in predictability and repeatability of refractive effect. In Phase I, we will perform an in vivo acute study in five subjects. In Phase II, we will perform an in vivo chronic study with a 3- month follow-up period. This work will support our application to the FDA for an Investigational Device Exemption.